Neurological diseases and disorders affect brain function. Many efforts have been made to develop curative or ameliorative therapies for these diseases and disorders; however, no comprehensive or universally curative therapy has been developed, even though there are numerous pharmacotherapeutic approaches that have been proven to be effective against various different diseases and disorders.
Huntington's disease (HD) is an inherited disease of the brain that affects the nervous system. It is caused by a defective gene that is passed from parent to child. The HD gene interferes with the manufacture of a particular protein known as ‘Huntington’ which appears to be crucial for proper brain development. The classic signs of HD include emotional, cognitive and motor disturbances. Huntington's is characterized by jerky involuntary movements (chorea), but sometimes causes rigidity without abnormal movements, changes in using the limbs (apraxia), loss of control of bodily functions and dementia, including a progressive deterioration of memory, speed of thought, judgment, and lack of awareness of problems and planning. There is no known cure for Huntington's disease. Although there are a number of medications to help control symptoms associated with HD such as emotional and movement problems, there is no treatment to stop or reverse the course of the disease. Huntington's disease has been recognized as a disease with a general membrane abnormality. A significantly elevated level and activity (10 fold increase) of Na,K-ATPase has been observed in membranes of erythrocytes and basal ganglia of Huntington's patients compared to that of normal (Butterfield D A, Oeswein J Q, Prunty M E, Hisle K C, Markesbery W R). Increased sodium, potassium adenosine triphosphatase activity in erythrocyte membranes in Huntington's disease. Ann Neurology, 4:60-62, 1978) fibroblast membranes obtained from the skin of Huntington's disease patients (Schroeder F, Goetz I E, Roberts E, Membrane anomalies in Huntington's disease fibroblasts. J. Neurochem. 43: 526-539, 1984).
Alzheimer's disease is a form of dementia—a neurodegenerative disease that damages the brain's intellectual functions (memory, orientation, calculation, etc.), but usually preserves its motor functions. In Alzheimer's disease, the mind gradually deteriorates, causing memory loss, confusion, disorientation, impaired judgment and other problems that may affect a person's ability to perform normal daily activities. The type, severity, sequence and progression of mental changes vary greatly. There is no known cure for Alzheimer's disease and no known way to slow its progression. For some people in the early or middle stages of the disease, medication such as tacrine may alleviate some cognitive symptoms. Aricept (donepezil) and Exelon (rivastigmine) are reversible acetylcholinesterase inhibitors that are indicated for the treatment of mild to moderate dementia of the Alzheimer's type. These drugs (called cholinesterase inhibitors) work by increasing the brain's levels of the neurotransmitter acetylcholine, helping to restore communication between brain cells. Some medications may help control behavioral symptoms such as sleeplessness, agitation, wandering, anxiety, and depression. These treatments are aimed at making the patient more comfortable. Although no medication is known to cure Alzheimer's disease, cholinesterase inhibitors may improve performance of daily activities, or lessen behavioral problems. Medications for the treatment of Alzheimer's disease currently being tested include estrogens, nonsteroidal anti-inflammatory agents, vitamin E, selegiline (Carbex, Eldepryl) and the botanical product gingko biloba. 
Triterpenes are known to possess a wide variety of therapeutic activities. Some of the known triterpenes include oleanolic acid, ursolic acid, betulinic acid, bardoxolone, maslinic acid, and others. The therapeutic activity of the triterpenes has primarily been evaluated individually rather than as combinations of triterpenes.
Rong et al. (Pharm. Biol. (January 2011), 49(1), 78-85) suggest oleanolic acid might be suitable for attenuating ischemic stroke. So et al. (Arch. Pharm. Res. (June 2009), 32(6), 923-932) suggest oleanolic acid might be suitable for the prevention and treatment of neurodegeneration in stroke. Li et al. (Brain Res. (February 2013), 1497, 32-39) suggest ursolic acid might provide neuroprotection after cerebral ischemia in mice. Garcia-Morales et al. (Arch. Pharm. Res. (July 2015), 38(7), 1369-1379) suggest that an extract of Bouvardia ternifolia should be further studied for treating Alzheimer's disease. Zhang et al. (Neuroscience Letters (2014), 579, 12-17) report that ursolic acid reduces oxidative stress following experimental subarachnoid hemorrhage. Qian et al. (Eur. J. Pharmacol. (2011), 670(1), 148-153) report that maslinic acid protects cortical neurons against oxygen-glucose deprivation-induced injury in rats. EP 2260851 A1 to Consejo Superior de Investigaciones Cientificas (Madrid, E S) suggests the use of oleanolic acid for the treatment of multiple sclerosis. Yoo et al. (Molecules, (May 2012), 17(3), 3524-38) suggest the use of terpenoids as anti-Alzheimer's disease therapeutics. Heo et al. (Mol. Cells (February 2002), 13(1), 5-11) suggest ursolic acid reduces amyloid beta protein-induced oxidative cell death. Chung et al. (Mol. Cells (April 2001), 11(2), 137-143) suggest ursolic acid appears to be a potent inhibitor of acetylcholinesterase in Alzheimer's disease. US 2007/0249711 A1 (Pub. Date. Oct. 25, 2007) to Choi et al. suggests the use of oleanolic acid and ursolic acid for improving brain functions to prevent and treat mild cognitive impairment and dementia.
Oleanolic acid is in a class of triterpenoids typified by compounds such as bardoxolone which have been shown to be potent activators of the innate cellular phase 2 detoxifying pathway, in which activation of the transcription factor Nrf2 leads to transcriptional increases in programs of downstream antioxidant genes containing the antioxidant transcriptional response element (ARE). Bardoxolone itself has been extensively investigated in clinical trials in inflammatory conditions; however, a Phase 3 clinical trial in chronic kidney disease was terminated due to adverse events that may have been related to known cellular toxicities of certain triterpenoids including bardoxolone at elevated concentrations.
Compositions containing triterpenes in combination with other therapeutic components are found as plant extracts. Fumiko et al. (Biol. Pharm. Bull (2002), 25(11), 1485-1487) discloses the evaluation of a methanolic extract of Rosmarimus officinalis L. for treating trypanosomiasis. Addington et al. (U.S. Pat. Nos. 8,481,086, 9,220,778, 9,358,293, US 20160243143 A1) disclose a supercritical fluid extract (SCF; PBI-05204) of Nerium oleander containing oleandrin and triterpenes for the treatment of neurological conditions. Addington et al. (U.S. Pat. No. 9,011,937, US 20150283191 A1) disclose a triterpene-containing fraction (PBI-04711) of the SCF extract of Nerium oleander containing oleandrin and triterpenes for the treatment of neurological conditions. Jager et al. (Molecules (2009), 14, 2016-2031) disclose various plant extracts containing mixtures of oleanolic acid, ursolic acid, betulinic acid and other components. Mishra et al. (PLoS One 2016 25; 11(7):e0159430. Epub 2016 Jul. 25) disclose an extract of Betula utilis bark containing a mixture of oleanolic acid, ursolic acid, betulinic acid and other components. Wang et al. (Molecules (2016), 21, 139) disclose an extract of Alstonia scholaris containing a mixture of oleanolic acid, ursolic acid, betulinic acid and other components. L. e Silva et al. (Molecules (2012), 17, 12197) disclose an extract of Eriope blanchetti containing a mixture of oleanolic acid, ursolic acid, betulinic acid and other components. Rui et al. (Int. J. Mol. Sci. (2012), 13, 7648-7662) disclose an extract of Eucaplyptus globulus containing a mixture of oleanolic acid, ursolic acid, betulinic acid and other components. Ayatollahi et al. (Iran. J. Pharm. Res. (2011), 10(2), 287-294) disclose an extract of Euphorbia microsciadia containing a mixture of oleanolic acid, ursolic acid, betulinic acid and other components. Wu et al. (Molecules (2011), 16, 1-15) disclose an extract of Ligustrum species containing a mixture of oleanolic acid, ursolic acid, betulinic acid and other components. Lee et al. (Biol. Pharm. Bull (2010), 33(2), 330) disclose an extract of Forsythia viridissima containing a mixture of oleanolic acid, ursolic acid, betulinic acid and other components. Wozniak et al. (Molecules (2015), 20, 20614-20641) disclose various therapeutic activities of ursolic acid. Liby et al. (Pharmacol. Rev. (2012), 64:972-1003) disclose various therapeutic activities of synthetic oleanane triterpenoids.
Oleanolic acid (O or OA), ursolic acid (U or UA) and betulinic acid (B or BA) are the three major triterpene components found in PBI-05204 (PBI-23; a supercritical fluid extract of Nerium oleander) and PBI-04711 (a triterpene-containing fraction 0-4 of PBI-05204). We (two of the instant inventors) previously reported (Van Kanegan et al., in Nature Scientific Reports (May 2016), 6:25626. doi: 10.1038/srep25626) on the contribution of the triterpenes toward efficacy by comparing their neuroprotective activity in a brain slice oxygen glucose deprivation (OGD) model assay at similar concentrations. We found that PBI-05204 (PBI) and PBI-04711 (Fraction 0-4) provide neuroprotective activity (FIG. 1). We then evaluated the neuroprotective activity of the three major individual triterpenes and of uvaol (Uva) individually in the OGD assay on an equimolar basis (FIG. 5). We found that OA provides higher activity than UA; whereas BA and Uva (uvaol) provide little to no activity at the concentrations tested. We found that the activity of UA in this assay exhibited variable activity in a concentration dependent manner. We postulated activation of nuclear factor erythroid 2 related factor (Nrf2)-dependent antioxidant genes as a potential mechanism for the underlying neuroprotective activity of PBI-04711 and the individual triterpenes. Therefore, employing an ARE-luciferase promoter-reporter assay, we determined the ability of those compositions to activate the Nrf2-ARE (antioxidant transcriptional response element) gene pathway in neurons using a corticostriatal primary neuronal co-culture system composed of the neuronal and glial cell types as in the brain slice OGD assay. We found (FIGS. 2A-2D) that PBI-04711 increased expression of canonical target ARE genes (glutamate-cysteine ligase, catalytic subunit (Gclc); NAD(P)H:quinone oxidoreductase 1 (Nqo1); sulfiredoxin antioxidant protein (Srx); and heme oxygenase 1 (Hmox1)) via activation of the transcription factor NRF2 that mediates the cellular antioxidant defense pathway. However, when comparing this activity of the individual triterpenes to that of PBI-04711 (FIG. 3), we found that UA appeared to be considerably more potent, as single agent, in inducing ARE gene expression compared to BA and OA, meaning the induction of Srx and Hmox1 is due more so to the activity of UA than of OA or BA, but UA still exhibits lower activity in the neuroprotection OGD assay. We found that while UA and BA are most active at gene expression, they are also very toxic at concentrations that are just 2-3-fold higher than concentrations required to induce gene expression. This means that UA and BA have narrow therapeutic windows. Our prior results suggested that UA and BA would likely be too toxic to achieve doses that would realize the full ARE-inducing activity in vivo. Our prior results also suggested that OA was relatively inactive on its own, so it would be unlikely that the combination of triterpenes (in PBI-05204 and PBI-04711) at their molar ratios could achieve substantially improved neuroprotective activity at doses that are not toxic at a cellular level.
U.S. Pat. Nos. 8,481,086, 9,220,778 9,358,293, and US 2016-0243143 A1 disclose the use of PBI-05204 for the treatment of neurological conditions. U.S. Pat. No. 9,011,937 and US 2015-0283191 A1 disclose the use of PBI-04711 for the treatment of neurological conditions.
Compositions containing plural triterpenes in certain molar ratios have been reported to be undesirable. Compositions comprising ursolic acid and oleanolic acid were evaluated to determine their impact upon platelet aggregation. Kim et el. (“Enhancement of platelet aggregation by ursolic acid and oleanolic acid” in Biomol. Therap. (2014), 22(3), 254-259) reported that the triterpenes potentiated platelet aggregation and “need to be used with caution, especially in the population with a predisposition to cardiovascular events”.
None of the art suggests a composition containing a combination of three different triterpenes selected from oleanolic acid, ursolic acid and betulinic acid, nor use of such a composition for the treatment of triterpene-responsive conditions, diseases, or disorders, wherein the triterpenes are present in the molar ratios as defined herein. None of the art recognizes the improvements provided by administration of such a combination of triterpenes as compared to administration of the individual triterpenes or administration of other combinations of triterpenes.